REG_AECH
ov7670_write(sd, REG_AECH, aech) +
{ REG_GAIN, 0 }, { REG_AECH, 0 },
ret = ov965x_write(ov965x, REG_AECH,
ret = ov965x_read(ov965x, REG_AECH, ®1);